Re: Access violation (0xC0000005) in PSQLODBC35W.DLL when calling SQLDescribeColW

(2010/11/10 13:04), Adrien de Croy wrote:
>
> Hi
>
> I have some helper classes to fetch fields from a record, a helper class
> to manage iteration through a result set.
>
> If I call my fetch helper function for some field ordinal it works fine
> the first time. If I call it again (without having called any method to
> change the current row in the result set) it fails on the same ordinal,
> but works on other ordinals.
>
> So, it looks to me like the fetch call is cleaning up the field data
> when you fetch,

If the helper function calls SQLGetData() for the column, yes.
SQLGetData() cleans up data which it returns to the caller and
returns SQL_NO_DATA when all data was returned to the caller.
You can divide into multiple SQLGetData() calls using this feature
when a column has a big data.

regards,
Hiroshi Inoue